Electric motors or generators having a stator secured within the housing of the rotor or generator are well known. A rotor coil mounted on a shaft is positioned within the stator and is rotatable relative to the stator about the longitudinal axis of the shaft. Liquid cooling can be provided for the motor or generator by passing fluid, such as water, through passages formed in the housing order to provide cooling for the stator. In order to enhance the cooling of the stator, the stator can be impregnated with a thermally conductive epoxy resin which promotes the thermal conductivity between the stator and the cooling fluid. EP-A-0327338 describes such a known arrangement. Because of the tight fitting of the stator in the housing, it can be difficult to impregnate the stator without leaving air pockets in the epoxy resin.